84-85 Trucks & 4Runners 2nd gen pickups and 1st gen 4Runners with solid front axles

Compression Test - High tension wire?

Old Nov 30, 2008 | 02:01 PM
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Compression Test - High tension wire?

In the FSM it says to disconnect the high tension wire from the ignition coil. I am not sure where this is. Is it necessary. I have read a little about people doing the test, but never heard anything about the tension wire.

Any help would be appreciated, thanks.
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Old Nov 30, 2008 | 02:20 PM
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From: north ridgeville ohio
move SLOWLY AWAY from the engine. put down the tools sir! i said put down the tools sir!!!!!!!!!!!!
we can talk this out.

ok seriously high tension wires would be the spark plug wires. and the COIL wire remove the coil wire from the coil to prevent the motor from starting during the test
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Old Nov 30, 2008 | 02:30 PM
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ok... I've just never heard that term. I'm new to this all.
It says I need to connect the high tension wire to a ground, is this necessary?
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Old Nov 30, 2008 | 02:43 PM
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From: north ridgeville ohio
3vze 6cyc motor
http://www.ncttora.com/fsm/1993/engine/66compress.pdf
4cycl motor
http://www.ncttora.com/fsm/1993/engine/6compress.pdf
i dont see it saying connect to ground
lets start by telling us what year model and engone you have
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Old Nov 30, 2008 | 04:13 PM
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it is an 85 22r.

I did the compression test and here are the results

1: 170
2: 174
3: 160
4: 160

I'd say that's pretty good for an old motor
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Old Nov 30, 2008 | 05:05 PM
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From: Temecula Valley, CA
"High Tension" is another way of saying "High Voltage", so that would be the center wire on the coil- the one that goes to the distributor center terminal. Connecting that terminal/wire to ground means that the high voltage will be sent to ground before it has the chance to harm someone (like you) working on the engine.

beyond that, your compression does not appear to be 'that' bad.
So, why are you testing your compression?
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Old Nov 30, 2008 | 07:01 PM
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Just got the truck. Seems like it should have a little more power. It kinda bogs up hills, but it is a carb 4cyl. Just checkin things out to make sure it'll be good for the winter.

I think the comp on the last two cylinders was a little lower because the engine wasn't really at operating temp. I started it up and let it idle until at temp and then I had to go to napa before they closed because a piece had broke. So the engine sat for 45 mins after it was at operating temp and cooled. It was prob another 10-15 minutes before I did the last two cylinders and it is about 40 degree F here.
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Old Dec 4, 2008 | 04:42 AM
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Hi, I always forget to have the throttle wide open when I do Comp Test. You might make a wire with two allegator clips, then pull the coil HT wire off the distributor and clip to the metal inside and then to ground. Also remove all spark plugs before doing the first comp test.
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